1. Field of the Invention
This invention relates to the testing of hydraulic actuation devices and more specifically to an acoustical testing apparatus to detect leakage and other problems in hydraulic actuators.
2. Description of the Prior Art
The hydraulic actuating rams used in many applications involving machinery are susceptible to a number of malfunctions or failures from different causes. For example, hydraulic fluid may leak around the seal between the piston and cylinder wall, the way may be worn, pitted from corrosion or scratched, or fluid may leak past actuator rod seals.
The technically simplest method to test a ram suspected of malfunction is to remove it from the system and take it apart to visually inspect and measure the condition of the parts of the actuator. This is, of course, costly and renders the system inoperable. It also requires exacting measurements to determine wear patterns and subjects the parts to possible damage during disassembly and assembly.
One better testing procedure is to immobilize the tailpiece of the actuator by bringing it up against an immovable object and allow hydraulic fluid to enter through one valve. Any fluid leaving the other valve is due to leakage. Similarly, the piston may be brought up to one end of the cylinder and the same procedure followed. However, this procedure may only be used at those positions where it is convenient to stop the travel of the ram and requires opening the system downstream of the ram to observe the fluid leakage. Thus, this technique requires partial disassembly and the possibility of missing a problem area completely.